Nina,
we have two dog parks here in Hunters Creek in Orlando and both are outdoors. I've had several portrait sessions there over the years but the environment is anything but conducive to good portraiture. There are dogs running around everywhere and even with my lighting and lots of props, it's hard to get the dogs to focus on the photographer.

I love your shot but I'm betting it's one of a lot of less usable and sellable images. Regardless, outdoors means you really can't use a backdrop and the existing backgrounds at both parks are less than photogenic.

On the other hand, I do go and take candids of the dogs in the parks and those sell pretty well. As do the shots of the kids on the soccer fields right next door to the dog parks. But when it comes to portraiture, I'm a bit of a control freak and dog parks are not an environment where you have much control.

Jim